Estimation is a key skill for all students to learn. You use this skill more in everyday life than most mathematical concepts. It allows one to check the validity of possible outcomes and gauge the reasonability of everyday life. It is a key to good judgement, and there are many ways to exercise this skill. Here are a few:
- Estimation Jar – An old standby for estimating number and volume, but one of the reasons this works so well is that it can be modified in so many ways. You can have different items in a jar (cookies, beans, pennies, jelly beans – though I’d recommend something not edible). Make it a contest. Give an award for the best or most creative thought process and explanation of how the calculated the number.
- Google Maps or Google Earth – Population Density. (This is a good activity also in that the point is not the final answer, but the reasoning and the presentation of the reasoning.) Have students pic a city or town to look over and make some guesses as to how many houses per square mile there are in that area. How many might there be if the town was 50 square miles? 100? How many people would you guess live there? (How many people per house? What type of housing is there? Single Family? Many Unit?).
- Estimating Length – Give groups different lengths of string (8 inches or less) and have groups estimate how many of their “units” (which if you are brave, you can encourage them to name) equal the length of the item. Create a class chart. A follow up exercise could be creating ratios between the created “units”. (In this case you don’t want them to use rulers to compare).
- Online Estimation Game (different math concepts – the one on length might be interesting for non-visual learners)
In these, think about offering them strategies, ways to make EDUCATED or REASONABLE guesses. List all variables you can think of which may change the answer. Use measuring tools (or create your own). Compare elements to things you know (use a “middle man”). Show your work. Use a calculator.